Physicians perform coronary angioplasty when a coronary artery has become partially blocked by a stenotic lesion. A stenotic lesion is an abnormal narrowing of an artery due to injury or disease.
The angioplasty procedure involves the introduction of a catheter system into the artery, by way of the femoral artery, under local anesthesia. The catheter system includes a guiding catheter and a dilating catheter. The end of the guiding catheter is inserted into the opening of the coronary artery.
The dilating catheter is passed through the guiding catheter into the coronary artery. The tip of the dilating catheter is passed through the stenotic lesion in the coronary artery. A balloon on the tip of the dilating catheter is then inflated with a fluid. The balloon forces the blockage open and enlarges the lumen, or passage, through the artery.
Sometimes during coronary angioplasty, the physician determines that he must replace the dilating catheter. The physician may have discovered that the existing balloon is too small or too large to force the blockage open.
Prior art methods use a conventional guiding catheter known in the art. The primary function of the guiding catheter is to assist in insertion of the dilating catheter into the coronary artery.
There are two lengths of guidewires generally available for use in coronary angioplasties: long guidewires and standard (short) guidewires. Prior art procedures require the use of a long guidewire to change balloons because there is no mechanism on prior art guiding catheters to maintain the position of the guidewire in the guiding catheter. Thus, when the dilating catheter is withdrawn from the guiding catheter, the dilating catheter pulls the guidewire out with it. Before a new dilating catheter can be inserted, the physician must reinsert the first guidewire or a replacement guidewire.
In addition, prior art procedures sometimes require replacing the existing balloon with a balloon having less flexibility. Replacing the balloon using prior art techniques uses additional time, exposing the patient to additional risks associated with prolonged anesthesia. Finally, prior art guiding catheters have no feature for maintaining the position of the guidewire in the guiding catheter if a dilating catheter must be removed.